Regulator says U.S. company breached antitrust law by limiting competing chip makers’ access to its patents

SEOUL—A South Korean regulator said it would fine Qualcomm Inc. about $853 million for alleged antitrust violations, the highest such penalty handed to an individual company here, as the U.S. chip maker faces global scrutiny over its patent-licensing business.

After a three-year investigation, the Korea Fair Trade Commission said on Wednesday that Qualcomm breached antitrust law by limiting competing chip makers’ access to its patents. The company also forced mobile-phone manufacturers into unfair license agreements by...